Metal workpieces may be cleaned in a blast cleaning apparatus such as that shown and described in U.S. Pat. No. 5,417,608, issued May 23, 1995 to Elliott, and the prior art described therein. The Elliott patent discloses a blast cleaning apparatus wherein a linear wire mesh conveyor, formed as a continuous belt, moves a workpiece in a straight line through a blast cleaning chamber. The wire mesh permits abrasive cleaning material to be directed at the workpiece by blast cleaning wheels located below the conveyor.
In the apparatus of the Elliott patent and similar prior art devices, one operator is required at a first work station upstream of the blast cleaning chamber to place onto the conveyor workpieces to be cleaned, and a second operator is required at a second work station downstream of the blast cleaning chamber to remove from the conveyor workpieces having been cleaned in the blast cleaning chamber.
Clearly, it would be more efficient if a single operator could perform both of these functions, namely placing workpieces to be cleaned onto the conveyor and removing cleaned workpieces from the conveyor. The disadvantage exists that no blast cleaning apparatus is presently known having a conveying surface with openings therethrough, such as a wire mesh conveying surface, in which the workpieces may be added to and removed from the conveyor at one work station by one operator.
Furthermore, conventional segmented conveyors, such as those typically used for conveying baggage at airports, or conveyor systems in which a plurality of linear conveyors meeting at angles of 90 degrees, would not provide satisfactory results in a blast cleaning apparatus due to expense and problems with abrasive cleaning material becoming lodged in such conveyors.